Car type furnace



J. H. KNAPP Oct. 11, 1932.

CAR Q TYPE FURNACE Filed July 30. 1930 2 Sheets-Sheet 2 m m m m m m m m m m m m m m m m ZVVENTOR: James f/fnapp, ay

Patentecl Oct. 11, 1932 UNITED STAES PATENT OFFICE JAMES H. KNAPP, OF BEVEELY IILLS, CALIFORNIA, 'ASSIGNOP TO JAMES H. KNAPP CO., OF LOS ANGELES, CALIEGRNIA, A. COR-POEATION OF CALFORHA CAR TYPE FURNACE Application` filed July 30,

'My invention relates to furnaces and relates particularly to a furnace having certain important features of Construction and operationwhich make it particularly useful in the ceramic art.

At the present time furnaces are used eX- tensively in the ceramic art for burning tile. One particular use of furnaces is for burning decorativetile, or, in other words, burning the enamelcoated thereon in order that the enamel maybe fixed or glazed. In view of the factthat in present furnaces a rapid change in temperature will crack the tile, the

cycle of operation is relatively slow, consequentlythe eiiiciency, so far as rate of production is concerned, is relatively low.

, t is one of the objects oi' my present invention to provide a furnace in which the cycle of operation is much faster than in the 207 ordinary type of batch furnace.

It' is a further object of my invention to provide a furnace in which the temperature throughout the heating chamber or treating chamber is dependably uniform. j

It is a still further object of my' invention to provide a furnace in which it is possible to rapidly cool the tiles without cracking them. This object of my invention is accomplished by designing the furnace so that a cooling gas, such as air, may be introduced in such a mannerthat the tile is evenly cooled. I have found that the reason for the breakage of the tile is that if it is removed from the furnace while it is at a comparatively high temperature the cooling is uneven, and 'for this reason the breakage occurs.

It is another object of my invention to providea furnace having means for passing air through 'the side walls of the furnace, thus assisting in the cooling operation. These passages in the side walls do not communicate with the interier of the furnace but are located between inner and outer portions of the furn ace walls.

It is another object of my invention to provide a furnace in which the cooling' medium, which is preferably air, is introduced into the combustion chamber and passes from the combustion chamber into the treating cham- 50 ber where the articles being burned are pres- 1930. Serial No. &71,733.

the heat evenly and uniformly removed from the combustion chamber and the treating chamber and consequently the temperature in the treating chamber will be reduced without suflicient Shock to the material to crack it. In this arrangement of my invention the cooling' air is first warmed or preheated in the combustion chamber, and as the heat is taken from the combustion chamber the passing air is warmed less, and consequently the air passing into the treating chamber is uniformly cooler and thus uniformly reduces the temperature throughout the treating chamber.

A further object of my invention is to provide a furnace of the type referred to in which the combustion takes place behind a bridge wall. This bridge wall is made of a material which becomes incandescent and the articles in the treating chamber are heated principal- .ly by radiation. V

Another feature object of my invention is to provide a furnace of the car type in which the car when placed in the furnace provides a central fiue through which the hot gases may escape.

A very important part of the invention resides in the arrangement of a central treating chamber and side combustion chambers on each side thereof, and a central vent for the gases, this vent, in the preferred form of my invention, being located in the car. i

Another object of the present invention is to provide a method of burning or treating tile, preferably decorative tile, in which the enamel or glazed surface retains the colors in their natural form and is comparatively brilliant.

This object of my invention is accomplished by performing in the heat-treating process the step of immediately and rapidly ceolin the tile when the melting temperature of the glaze or enamel has been reached. E have found that if the temperature in the turnacc i maintained at the melting temperature of the glaze or enamel, that the adapted to be moved into the furnace.

enamel will lose its luster and the colors will be unnatural and will be dull.

Another object of my invention is to provide a. method of heating a charge to a. desired temperature and then quickly and evenly cooling such charge without removing same from the heating device and without causing the charge to crack or be warped or otherwise injured, such as results when an uneven cooling occurs.

It is' a further object of my invention to provide a furnace of the character mentioned having acaron which the articles to be treated are placed which may be 'Conveniently and readily charged and discharged; that is, the articles maybe easily placed 'on and removed from the car. y

the preferred form of my inventomi 'accomplish this object by forming the setters as a part of the car rather than separately, as is 'the present practice. In my invention the setters remain ntact and 'only the articles are handled, which ehnnnates con- 'siderable labor in loading and unloading.

Further objects and advantages of the furhace of my invention reside in the details of Construction and in the description which is to'follow. These various objects and advan- 'tages will be pointedout in connection with the structure.

Reterring to the acconpanying drawin'gs,-

' Fig. 1 is a longitudinal View through my' invention.

v Fig. 2 is a longitudin'al section showing the means for cooling the walls 'o f the furnace and showing the interier of the combustion Chamber, p

Fig. 3 is a cross-'sectional View through my invention i Fig 4 is an end view thereof pa'rtly in section I i i i I i Referring to the drawings in detail, the numeral 11 represents a foundation on which `V the furnace proper is supported. The furnace' has afioor 12 which rests on the foundation 11. *Extending Upward from the floor 12 are side walls 13 and end walls 14. Supported at the upper ends of these walls 13 and 14 is a curved top wall 15. Formed the foundation 11 longitudinally of the 'urnace'is a cavity 17', and formed'in the floor 12 above the ca'vity 17 is a .longitudinal opening 18. For-med in the end walls 14 ot the furnace are entrances 20 which are adapted to be closed by vertically slidahle doors 22. i

Thenumeral 23 indicates a car which is The car 23' has a `horizontal body 24 which is supported on wheels 25, which wheels 25 operate on tracks 2:3 placed in the bottom of the I 'cavity-17. The. body 24 is longer than the turnace'and ends 27 thereot extendthr'ough K the entrances 20 to the 'eXteror of 'the furnace.

and side combustion chambers 37.-

tween thesections 30 Extendng upward from the body 24 are Walls 28 which rest in the entrances 20 when the car is placed in the furnace and therefore close these entrances and assist in retaning the hoat in the furnace. Arranged between the walls 28 in two sections 30 aresetters 31 which support articles 32' which `are* to be heat-treated, or, in the case of decorative tile, burne'd.

' Extendng upward from, the floor 12 adj'a cent the side walls 13 are bridge walls 34 which are made of heat resisting and heat conducting material such 'as carborundum. As shownbest in Figo 8, the bridge walls 34 termnate below the top wall 15. These ;bridge walls 34 divide the interior of the urnace into a central treatingchamber 36 Formed horizontally through the side-walls '13 and connected to the lower parts of the c'onbustion chanbers 37 are openings 38 which receive burners 39. 'These burners 39 supply 'he combuston chambers with a combustible gas and combustion supporting' gas in order that a fiarne maybe produced in the co mbustion chambers. The gases of combustion are removed from the furnace through a central fiue 41 which is formed longitudnally in the body 24 of the car 23. This fine 41 extends longtudinally of the car body and the treating chamber 36,and the ends thereof are connected to crossfiues '42 provided in the ends 27. The end portions of the cross-flues '42 are joined to vertical fiues 43 which are in com'- municaton with stacks 44 whichin thepres cnt emhodiment of my invention are connected to the doors 22. suitable 'scaling means, such as 45, is provided where the stacks engage the end portions 2701:' the body of the car in order to prevent leakage. It will be noted that the width of the body of the car s substantially that of the opening 18 'Therefore, the body acts as a closure for one portion of the entrance 20. e The portion of the entrance 20 above the body of the car is i "These openings 47 communicate with the lower part ofthe treating chamber 36`be- 'and the car is moved on the tracks 26 until' it reaches the position shown in Fig. 1'. *At

of the setters supported this time the doors 22 are lowered in order to close the entrances 20 in order to bring the stacks into engagement'With the'ends of the car. The burners are then set into operation and a flame is produced in each of the combustion chambers 37. The combustion chambers are'made separate from the treating chamber in order that combustion will take place away from the articles to be treated and in order to prevent carburation of them. The combuston taking' place in the .combustion chanbers heats the bridge walls 34: to an incandescent heat, which heat radiates towards the central vertical plane of the treatin'g chamber and thus heats the articles 32 by radiation. The products of conbustion pass upward from the combustion chamber, as indicatedby arrows 50, and pass inwardly over the top of the bridge walls 34: to

the upper partof the treating chamber 36.

The products of combustion then pass downward, as indicated by arrows 51, between the sections and pass outward through the openings 47 into the fine 41. The hot gases therefore assist by convection in heating the articles 32. It will be noted that these hot gases come into contact with the portions of thearticles 32 which are most remote froni the bridge walls 34 and therefore assist in obtaining and maintaining an even 'temperature. V

Ilion the furnace is being used for burning decorative tile, which use is the principal use of my invention, the temperature is raised to'the Inelting point of the enainel which is coated on the decorative tile. he manner of nanufacturing decorative tile is 'well known, and one of the steps consists in painting enamel on the surface of the tile, which enaniel must afterwards be burned in order to sniooth itout and to make it hard.

In my furnace the temperature is raised :to the melting point of the enamel. In view of the specific arrangement illustrated, the temperature at all points of the treating chaniber is the same. Therefore, the enamel on all pieces of tle is liquefied at the same time. When the enamel is liquefied, it will flow on the surface of the tilc and become smooth. I have discovered that a better quality of decorative tile is produced when it is cooled immediately after the melting temperature of the enamel is reached. This is probably because of the fact that while the enamel is in a liquid state some Chemical change or evaporation takes place which deprives the enamel of its true color and luster. The furnace of my invention is very quickly cooled by the following means and in the following manner.

' As shown best in Fig. 2, the end walls 14 are provided with cooling gas passages which connect to the ends of the comhustion ohambers 37 at the lower parts thereof. The outer ends of the cooling gas passages are closed by suitable valve plates 56. If desired, a Conduit may be connected to the cooling gas passages 55 and suitable flow-causing means enployed to force cooling air through the cooling gas passages into the combustion chambers. When it is dcsired to cool the furnace and the articles 32 therein, which is the case in decorative tile, immediately after the m-elting temperature of the enamel is reached the hurners 39 are shnt down and the valves 56 of the cooling gas passages 55 are openec. Cooling gas, which in the present instance is air, will flow into the ends of the combustion chanbers 3. either by the draft efiect of the furnace or by a mechanical flow creating means and this cooling air, because it first passes into the combustion chambers, derives a certain amount of heat therefrom and its temperature is raised. This cooling gas then fiows through the seine path as d scribed in connection with the products of combustion and in passing through the treating chanher cools the articles 32 therein. As the cooling gas continues to flow through this cycle, the temperature in the combustion chanbers 37 is reduced and the bridge wall 34 is cooled. It will be seen that as the operation goes on the air which reaches the treating chamber 36 gradually becomes cooler because of the fact that the heat taken on in the conbustion chanber is less as the cooling operation continues. In a relatively short period of time the temperature in the treating chamber the temperature of the articles 32 suiicently reduoed so that the articles can be exposed to atmospheric temperature without danger of craclring, and the doors are then elevated and the car is removed.

The cooling operation is an important part of the invention. lt is quite important to the operation of 'the furnace that the cooling air be introduced into the combustion chambers. The reason for this is that the cooling air is preheated in order that the change in temperature in the treating chainber 36 may not be too sudden, and in order that the articles 32 will not receive a shock by a stream of cold air owing into contact with them. The first cooling air which passes into the treating chamber 36 is but slightly cooler than the temperature in the treating chamber but as the cooling operation continues the cooling air which fiows into the treating chamber becomes gradually cooler and cooler until the temperature has been sufiiciently reduced to permit the articles to be brought into contact with atmospheric temperature.

I also provide an additional means for cooling the furnace. This means constitutes vertical cooling passages 60 which are formed in the side walls 13. The lower ends of the cooling passages 60 connect to the exterior at 6l and the upper ends connect 'to the exterior at 62. These passagcs 60 are shown in Fig. 3 and are shown in the left-hand part of Fig. 2. Valve means 64 and 65 are provided for the passages and are opened only when the cooling operation is taking place the valves 64: and 65 are opened and a flow of cooling air or gas will flow through the cooling passages 60, thus reducing the temperature of the walls.

In the preferred form of my invention, as shown heroin, the setters 31 form an integral part of the car. Horizontal plates made from a heat-resistant material are supported in spaced relation by blocls 81 wh ch are made from a heat-resistant material. The parts may be Secured together so as to be a part of the'car by a mortar eementng material. The articles 32 are placed on the plates 80 and removed in a horizontal direction. The setters are never removed from place, which reduces to a considerable eXtentthe labor of charging and dischargng the car. Furthermore, a breakage of one of the plates will not disturb the others.

In the foregoing description have described and in the drawings I have shown. the prefe'rred form oi' my inventon. I have mentioned the use of my furnace in connection with the ceramic and particularly V inconnecton with the manufacture of decorative tiie. I wish it to be understood that 'do notintend to limitmyself to the spcchc 1 p details shown and described, nor do 1 IDLG u 'to limit myself to a furnace hch is capable V of use onlyin the ceramic art. I ully under stand that my invention is useful in other arts wherein the features and advantages provided by my invention are or" value. r

I claim as my nvention: I e y l. Ina furnace of the class described, the

combination of: `wails forming a .treating chamber and an entrance therefor; means for heating said treating chamber; and a 'car adapted to be placed in said treating a chamber, one end of said car being adapted to extend through said entrance, said car 'having a flue through which 'the gas passes' from said treating chamber, the exhaust end of said fine being in the end of said car part of said treating chamber.

3. In a furnace of the class described the combination of: walls 'defining a treating chamber; walls forminga combustion chamber, and including a. radiation wall between said treating chamber and said' conb'ustion 'chamberg'means for supportnga charge in said treatmg chamber V ad acent sa d radiae tion wall, so that said charge may be heated by radiation; combustion means in said combustion chamber for heating said radiation wall, there being fine means connected to said combustion chamber and said treating chamber for directing hot gas from said combustion chamber into adjacencywith the portion oi' said charge remote from said radiation wall; and means for directing a cooling gas into .the lower part of said combustion chamber, said cooling gas passing through said fine means and into contact with said charge, and said cooling gas continuously taking heat from said radiation wall.

4:. 'In a furnace of the class described, the combination of: walls defining a treating chamber; walls forming a combustion chamber, and including a radiation 'wall between said treating chamber and said combustion chamber; means ;tor supporting a charge in said treating chamber adjacent said radiation wall, sothat said chargemay be heated by raoiation; and combustion means in said combustion chamber for heating said radiation wall, there being fine means connected to said combustion chamber and saidtreating chamber `for directing hot gas from said combustion chamber into adjacency with the portion of said charge remote from said rad'iation wall, and there being a cooling passage in said walls forming said treating chamber and said combustion chamber, said cooling passage having an inlet and outlet incommunication with' the eXterior of said furnace. i r i 5. in. a furnace of the class described, the

combination of: walls defining a treating chamber; walls forming a combustion chamber, and including a radiation wall between said treating chamber and said combustion chamber; means for supporting a charge in said treating chamber adjacent said radiation wall, se? that said charge maybe heated by radiation'; combustion means in said combustion chamber for heating said radiation i wall, there being fine means, connected to said combustion chamber and said treating chamber for directing 'hot gas fromsaid combustion chamber into adjacency with the portion of said charge remote from said radiation wall, and there being\ a cooling passage in said walis forming said treating chamber and said combustion cham'ber, said cooling passage having an mlet'and outlet in communication with the exterior of said furnaee; and means for directing a cooling gas into the lower part of said combustion chamber, said cooling gas passing through said fine means and into contact with said charge, said cooling continuously taking heat from said radiation wall.

In testimony whereof, I have my hand at Los Angeles California, this 26th day of July,l93 .a a i i V i JAMES. H. KNAPP.

hereunto set 

